We are investigating the control of morphogenesis and differentiation in Dictyostelium discoideum and other cellular slime molds. Work in the current year will include analysis of the control of aggregation using artificial cyclic AMP signals and measurement of the parameters of the natural signal. Properties of mutants defective in aggregation will be examined. Control of later stages of development by the aggregate tip, which acts as an organizer will be analyzed and quantitative models for aggregation and multicellular morphogenesis completed.